Variable pitch fan blade assembly



J. J. BRANDON ET AL VARIABLE PITCH FAN BLADE ASSEMBLY Aug. 23, 1949.

2 Sheets-Sheet 1 Filed June 9, 1948 I rear/ 53%,

r I hmimhi z I n 0 Y .m MW Rd W p wn w N a p. 1 M r% 4 m Bf JJ n, my a JR Y B J. J. BRANDON ET AL VARIABLE PITCH FAN BLADE ASSEMBLY Aug. 23, 1949.

2 Sheets-Sheet 2 Filed June 9, 1948 n 4 8 7 0 4 3 M 0 46 wa 4 4 4 W W. H a 22 3 1R H J I J A a W M 3 l :6 L/ 3 O: M m mm M 0 w I I ,3 a X E 7 :7 Q I 4 3 w 3 7i, 3 2 3 INVENTOR.

A TTORNE Y Patented as. 1949 2,479,668

UNITED STATES PATENT OFFICE VARIABLE PITCH BLADE ASSEMBLY Joseph J. Brandon, Carteret, N. 1., and Robert J. Etherington, Detroit, Mich., asslgnors to Evan's Products Company, Plymouth, Mich a cora snap ring it.

poratlon of Delaware Application June 9, 1948, Serial No. 31,968

or internal Claims. (Cl. 170-46037) of the invention is shown on the accompanying drawings, in which Figure 1 is a fragmentary front end elevation of a variable pitch fan blade assembly, parts being broken away to show the operating mechanism, several of the fan blades being omitted;

Figure 2 is a vertical sectional elevation substantially on the line 22 of Figure 1; and

Figure 3 is an enlarged sectional view on the line 3-3 of Figure 1.

The illustrated embodiment of the invention comprises a variable pitch fan blade assembly A, which may be suitably mounted in advance of an internal combustion engine, for example, be tween the usual radiator and. the engine block, and is driven from the engine, as will ,be readily understood by those skilled in the art. For example, no represents the hub of a drive sheave,

' which is secured by bolts II to the hub ii of the fan blade assembly. The hub I2 is formed of two sections I211 and lib which flatly abut against each other, a series of bolts I3 securing the peripheral edge portions of the hub sections together. The hub i2 is in the form of an annulus having an annular central apertured portion it and arranged equi-distantly of the outer portion of the hub are fan blades l5, which are secured to brackets it provided respectively with a suitable counterweights ll. Each fan blade bracket has a stud shaft l8 which extends into a cylindrical socket it formed in the hub it, onehalf of the socket being formed in each of the hub sections Ma and i211.

interposed between the stub shaft i8 and the inner walls of the socket is is a ball bearing unit it, which is heldagainst shifting movement by The stub shaft i8 is shouldered at 22 to bear against the upper end of the bearing unit at. A flexible non-metallic washer 23 has a portion recessed in the hub l2 and wipes 2 IE to provide an oil seal for militating against the loss of lubricant from the bearing unit 23.

The lower end portion of the stub shaft I3 is reduced and screw-threaded, as indicated at 24, to receive a nut 25 which bears against the inner race of the bearing unit 20. On the lower end of the screw-threaded shaft portion 24 is a reduced pin-like extension 26, which fits a central aperture in the disc 21, a pin 28 securing the disc 2'! to the extension 26 so that the disc and stub shaft turn together.

Having a press flt in the disc 2'1 eccentrically thereof is a pin 29, which depends beyond the lower side thereof and extends relatively loosely into an opening or socket 30 formed in an intermediate portion of a shoe 3|. The shoe 3| has an upstanding boss 32 at the upper end to bear flatly against the under side of the disc 21. The shoe is longitudinally elongate as indicated on Figure 1 and fits into a channel 33 formed in the periphery of a sleeve, generally indicated at 34, which, as will hereinafter appear, is shiftable axially or horizontally (Figure 2) within the central opening 14 of the hub. It will be manifest that axial movement of the sleeve 34 within the hub opening [4 (to the right or left of Figure 2) imparts similar movement to the shoe 21, thereby causing, through the eccentric pin 29, rotary motion of the fan blade l5, thereby to vary its pitch. Although a single' fan blade and its mounting has been described, it will be understood that several equi-distantly spaced fan blades are carried by the hub I 2 and are con- .jointly rotated about their axes to vary the pitch thereof.

The sleeve M is fabricated from a pair of metal stampings 35 and 36 formed with flat abutting surfaces, which are spot-welded together as indicated at 31, a number of spot welds being employed to produce a rigid structure. The outer edge or rim portion of each stamping is bent outwardly to provide oppositely extending annular rim flanges 38 and 39, which bear flatly against and are slidable along the wall of the opening It. Adjacent the rim flanges 38 and 39,

the base am of each shoe is also curvilinear to conform to the curvature of the channel, thereby to increase the bearing contact between the shoe against the enlarged portion of the stub shaft and the base of the channel. The central pors'nvaeea tion of the sleeve stamping 35 is bent to form a hub 40, the extreme end portion being flanged inwardly, as indicated at 4|. The central portion of the sleeve stamping 38 is formed with a relatively short hub portion 42, which intimately engages a portion of the outer surface of the tubular portion 40.

Pressed into the hub portion 42 and abutting against the flange 4| is a ball bearing unit 43 and fixed to the inner race of the bearing unit 43 is a flange sleeve 44, which is internally screwthreaded to receive the threaded end portion of an actuating rod 45. Secured by the bolts H to the outer face of the hub I2 is a closure plate 48 against the inner face of which bears the smaller end of a conical coil spring 41, the opposite end of the spring 41 hearing against the sleeve 34 adjacent the rim flange 39; A spring-tensioned relief valve 48 is mounted centrally of the cover plate 48.

The rod 45 may be connected to and actuated by a thermostat (not shown) which is responsive to the temperature of the engine cooling liquid so that upon increase in temperature of the liquid, the rod 45 is moved to the right of Figure 2, thereby causing the fan blades I5 gradually to move into pitch in order to increase the volume of air supplied for engine cooling purposes. Upon decrease in the temperature of the engine cooling liquid, the rod 45 is moved to the left of Figure 2, allowing the coil spring 41 to actuate the sleeve 34 to the left of the figure. thereby gradually decreasing the pitch of the fan blades. Reference is hereby made to the patent to Earley et al. No. 2,437,810 dated March 16, 1948, for a more complete description and illustration of a suitable thermostatic control device.

An important characteristic of this invention resides in the actuating sleeve 34, which is simply and inexpensively constructed from metal stampings, which are secured together to produce a sturdy and reliable structure and one which is extremely light in weight, thereby obviating difflculties and expense heretofore occasioned in casting and machining of this part. The improved mounting of the shoes in the actuating sleeve enhances the efiiciency of the assembly. Another feature of exceedingly practical advantage resides in the support for the fan blade carrying shaft, not only facilitating assembly but increasing the sturdiness of the structure to cope with vibration set up in the operation of the assembly.

It is to be understood that numerous changes in details of construction, arrangement and operation may be effected without departing from the spirit of the invention especially as defined in the appended claims.

What we claim is: I

1. A variable pitch fan blade assembly comprising a centrally apertured rotatable hub, a plurality of fan blades arranged radially of said hub, a stub shaft for each fan blade mounted in said hub for rotary movement, a disc rotatable with said stub shaft, an eccentric pin on said-disc and depending therefrom, a sleeve in the apertured portion of said hub for axial shifting movements, said sleeve comprising a pair of metallic stampings secured together, each stamping having a peripheral rim flange for sliding engagement with the wall of the hub aperture, an annular channel on the periphery of said sleeve, a shoe for each fan blade fitting said channel and having a bearing socket receiving the respective eccentric pin, each shoe being curved to co'nform to the curvature of the channel thereby to provide a substantial bearing surface contact between the shoe and the channel, and means for imparting axial shifting movement to said sleeve.

2. A variable pitch fan blade assembly comprising a centrally apertured rotatable hub, a plurality of fan blades arranged radially of said hub, a stub shaft for each fan blade mounted in said hub for rotary movement, a discrotatable with said stub shaft, an eccentric pin on said discand depending therefrom, a sleeve in the apertured portion of said hub for axial shifting movements, said sleeve comprising a pair of metallic stampings arranged in abutting relation and fixedly secured together, said stampings providing therebetween an annular substantially U- shaped channel, a shoe for each fan blade fitting said channel and having a bearing socket for the respective eccentric pin, each shoe being curved in conformity to the curvature of said channel, and means for imparting axial shifting movement to said sleeve.

3. A variable pitch fan blade assembly comprising a centrally apertured rotatable hub, a plurality of fan blades arranged radially of said hub, a stub shaft for each fan blade mounted in said hub for rotary movement, a disc rotatable with said stub shaft, an eccentric pin on said disc and projecting therefrom, an actuating sleeve in the apertured portion of said support for axial shifting movements, said sleeve comprising a pair of metallic stampings fixedly secured in abutting relation, eachstamping having annular rim flanges for sliding engagement with the apertured wall of said hub, a peripheral channel formed by the said flanges and extending circumferentially of the sleeve, a shoe for each fan blade fitting said channel and having a bearing socket for the respective eccentric pin, and means for imparting axial shifting movement to said sleeve.

4. A variable pitch fan blade assembly comprising a centrally apertured rotatable hub, a plurality of fan blades arranged radially of said hub, a stub shaft for each fan blade mounted in said hub for rotary movement, a disc rotatable with said stub shaft, an eccentric pin on said disc and projecting therefrom, an actuating o sleeve in the apertured portion of said support for axial shifting movements, said sleeve comprising a pair of metallic stampings fixedly secured in abutting relation, each stamping having annular rim flanges for sliding engagement with the apertured wall of said hub, a peripheral channel formed by the said flanges and extending circumferentially of the sleeve, a shoe for each fan blade fitting said channel and having a bearing socket for the respective eccentric pin, a central 0 hub sleeve integral with said stampings respectively, an anti-friction bearing unit within said hub sleeve, rod means engaging said anti-friction bearing for shifting said actuating sleeve in one direction, and a spring for shifting said actuating sleeve in the opposite direction.

5. A variable pitch fan blade assembly comprising a centrally apertured rotatable hub, a plurality of fan blades arranged radially of said hub, a stub shaft for each fan blade mounted in said hub for rotary movement, an anti-friction pin on said disc and projecting therefrom, an actuating sleeve in the apertured portion of said support for axial shifting movements, said sleeve comprising a pair of metallic stampings fixedly secured in abutting relation, each stamping having annular rim flanges for sliding engagement with the apertured wall of said hub, a peripheral channel formed by the said flanges and extendin circumierentially or the sleeve, a shoe for each fan blade fitting said channel and having a bearing socket for the respective eccentric pin. a central hub sleeve integral with said stampings respectively. an anti-friction bearing unit within said hub sleeve, rod means engaging'said anti- JOSEPH J. BRANDON. ROBERT J. ETHERINGTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number iriction bearing for shifting said actuating sleeve 15 2,437,810

Name Date Dewey free. 17. 1940 Dewey et al Apr. 20, 1943 Dewey Aug. 1, 1944 Earley et a1. Mar. 16. 1948 

